Preparation of 1,1,1-trichloroethane

ABSTRACT

1,1,1-Trichloroethane is prepared in the novel process comprising reacting by contacting chlorine monoxide with CH3CH2Cl and/or CH3-CHCl2. The reaction is conducted in liquid phase and at a temperature of from about - 20* to about 80* C.

iJite States Patent [1 1 Kochanny, Jr. et al.

[ PREPARATION OF 1. l l -TRICHLOROETHANE [75] inventors: Gerald L.K0channy,Jr.; Thomas A. Chamberlin, both of Midland, Mich.

[73] Assignee: The Dow Chemical Company,

Midland, Mich.

[22] Filed: Aug. 17, 1972 [2]] Appl. No.: 281,475

Related US. Application Data [63] Continuation-impart of Ser. No.799,484, Feb. 14,

I969, abandoned {52] US. Cl. 260/658 R, 204/163 R [51] Int. Cl. C07c17/10 [58] Field of Search 260/658 R, 659 R;

[ Mar. 18, 1975' [56] References Cited UNITED STATES PATENTS 3,019,1751/l962 Haefner et al. 204/163 R 3,535,394 10/1970 Pregaglia et al260/658 R OTHER PUBLICATIONS Tanner et al., JACS 89, pp. l2ll25(1967)OD1.A5.

Primary Examiner-Bernard Helfin Assistant Examiner-Joseph A. BoskaAttorney, Agent, or FirmL. Wayne White 57] ABSTRACT 9 Claims, N0Drawings I PREPARATION OF I l ,l-TRICHLOROETHANE CROSS-REFERENCE TORELATED APPLICATION This application is a continuation-in-part of ourcopending U.S. patent application Ser. No. 799,484, filed Feb. 14, 1969.and now abandoned BACKGROUND OF THE INVENTION l,l,l-Trichloroethane is aknown compound which is commercially used as a solvent.

There are several known methods for preparing the compound. The mostcommon methods comprise chlorinating chloroethane (orl,l-dichloroethane) with chlorine under special conditions. For example,Haefner et al. (US. Pat. No. 3,019,175) teach that chlorine reacts withl,l-dichloroethane in the presence of actinic light and in certaindirective chlorination solvents (e.g. CS to producel,l,l-trichloroethane.

The problem with such prior art processes is that they produce acidicby-products (such as HCl) and considerable amounts ofl,2-polychlorinated ethanes in addition to the desired product. Suchcontaminants are undesirable and have to be removed, typically by acidscrubbers and a distillation step. Economically, the 1,2-polychlorinated ethanes thus produced are undesirable because thecommercial market for them is currently quite small.

A need therefore exists for a method of manufacturing1.1.l-trichloroethane essentially free of 1,2- polychlorinated ethanes.

SUMMARY OF THE INVENTION A new process has now been discovered whereinl,l,l-trichloroethane is prepared in excellent yields and purity, i.e.substantially free of 1,2-polychlorinated ethanes. The novel processcomprises reacting by contacting in liquid phase chlorine monoxide (C1with chloroethane and/or l,l-dichloroethane.

Our discovery that C1 0 would selectively chlorinate chloroethane and/orl,l-dichloroethane was most surprising in view of Tanner et al. (J. Am.Chem. Soc. 89, l2l 1967)).

Tanner et al. produced dichloropropanes and dichlorobutanes bycontacting (a) C1 0 and (b) lchloropropane or l-chlorobutane in a molarratio of 1 mole of (a) per l0 moles of (b). The reaction was conductedin CCl, solvent and in the presence of actinic light. Attempts to runthe reaction in the dark and/or in the presence of atmospheric amountsofoxygen were unsuccessful in that the reaction rate was much too low tobe practical. Tanner et al. obtained in every instance a mixture ofdichloropropanes (or dichlorobutanes). Tanner er al. did not report andapparently did not observe any l,l,l-trichloropropanes or any 1,1,1-trichlorobutane (or any other trichlorinated isomer) produced in thecourse of the reactions. Such data are unexpectedly contradictory to theresults we observe in the reaction of Cl O with chlorethane and/or 1,1-dichloroethane, the adjacent homolog.

Our novel reaction is represented by the equations:

lii)

We prefer to conduct the reaction under substantially anhydrousconditions since water lowers the reaction rate and reacts with C1 0 toproduce HOCl. The latter compound is far less selective chlorinatingagent than C1 0 in the instant process and could produce undesirableisomers in competing side reactions. Under substantially anhydrousconditions, little if any acidic by-product is formed and the specialequipment (e.g. acid scrubbers) needed in the prior art processes can beeliminated. This is a substantial economic and procedural advantage.

The water formed during the course of the reaction is easily removed byconventional means. E.g. water can be removed by (l) conducting thereaction in the presence of a dehydrating agent, e.g. Na SO CaSO andothers in the known class of drying agents, (2) azeotropic distillation,(3) physical liquid-liquid phase separation, or by other methods knownto those skilled in the art.

We have discovered that C1 0 selectively chlorinates the l-carbon atomof l-chloroethane and 1,1- dichloroethane under any set of conditionswherein the rate of chlorination is higher than the rate of thermaland/or photo-initiated decomposition of C1 0. For this reason, thereaction is preferably conducted in the dark (or substantial absence ofactinic light) and at a temperature where the rate of thermaldecomposition of C1 0 is relatively low.

By actinic light is meant radiation of short wave length, as occurs inthe visible and ultraviolet portion of the spectrum, that possessessufficient energy to cause chemical reaction. C1 0 decomposes rapidly inthe presence of actinic light to form an unresolved mixture of productswhich include chlorine, free radicals of chlorine and otherchlorine-containing species. Various species in this unresolved mixtureare nonselective chlorinating agents in the reaction with l-chloroethaneand/or 1,1-dichloroethane.

The rate of thermal decomposition of C1 0 increases with increasingtemperatures, and above about 140C C1 0 has been known to decomposeexplosively. The thermal decomposition products are a similar unresolvedmixture of nonselective chlorinating agents.

A suitable reaction temperature is one sufficiently low that the rate ofthermal decomposition is lower than the rate of chlorination and yet issufficiently high to promote the chlorination reaction. A reactiontemperature between about 20C and about C is generally satisfactory. Apreferred temperature range is from about 0C to about 50C and the mostpreferred temperature range is from about 10C to about 40C.

At temperatures in the lower portion of the suitable temperature range,e.g. 0C, and in the absence of actinic light, the selectivity of C1 0 inthe subject process is very high, almost quantitative, but the rate ofchlorination is low. At higher temperatures, such as 50C and above, thedegree of selectivity of C1 0 in the subject reaction is lower but therate of chlorination is substantially increased.

The stoichiometry of the reaction is shown by equations (i) and (ii)above. Substantially any molar ratio of reactants can be used (e.g. fromabout 1:20 to about 20:1 However, in order to maximize the producutionof CH -CCl we prefer to use a stoichiometric amount or excess of C1 0(e.g. up to about a 5-fold excess) and we most prefer to use astoichiometric amount of C1 0.

The reaction time varies inversely with the temperature and thereforemay vary from a few minutes to several days. Accordingly, the reactantsshould be maintained in contact with each other until the desiredreaction product is formed.

The reaction is conducted in liquid phase, which means the gaseous orliquid C1 may be admixed with liquid CH -CH CI and/or CH -CHCl eitheralone or in solution in an inert liquid. 1,1 ,l-Trichloroethane is 4EXAMPLE 2 Reaction of C1 0 with CH CH Cl (CCl solution).

A stock solution of C1 0 was prepared by dissolving CI O (gas).generated as described in Example I in CCl at 0C to a 1.444 Molarconcentration. A reaction mixture having equimolar amounts of Cl O andCH CH Cl was prepared by mixing 0.0488 moles of inert in the reactionand is the preferred solvent, if a CHaCHZCl with? 31 allquot Ofthe aboveClZO'CCL solvent or diluent is used. Other suitable solvents includeperhalogenated hydrocarbons, e.g. CCl

Pressure on the reaction is not critical so long as the reaction mediumis liquid.

solution. Portions ofthe reaction mixture were allowed to react atvarious temperatures. in the dark. and in vessels open to theatmosphere. The results are summarized in Table II.

TABLE ll (Mulnr Rzltiu ('l. (H..(H. ,(l l l) Rxn. Rxn 'l'ime lump NU(Hrs) 1C) A B [5 l 1 162 u 2*) in to xs 1x x4 (I no (1 It I 6 25 3 II 3(i1 ll 1 332 3.5 1 40 724 77 1 1 1195 (1114 4 l 4!) 29.76 20h 168; It)(lit) A 5 67 411 41H 1491) 17x 311" 117$ (1 1 IILICHI A ('H ('ll('lln\ul'1| H (1141101. (11ml '1) (11.001. ("1.11 '11 l) ('l('ll ,('ll..('l tmul 'I'] E ('I('l1. .(|l(1 (mol '11 l 4 others (mnl it Theatmosphere above the reaction mixture may sur- EXAMPLE 3 prisinglycontain oxygen without detriment to the reaction rate and selectivity ofC1 0 in the subject reaction. An inert gas, such as nitrogen, may alsobe used.

SPECIFIC EMBODIMENTS: The following examples further illustrate theinvent1on;

EXAMPLE I. I 7 Reaction of Cl O with CH CH CI (Neat).

Cl- O (gas) was generated according to the method of Cady l) anddissolved in ethyl chloride at -78C over a period of 2 hours. Duringthis time, the concentration ofCl O rose to 3.4 Molar. Portions of thisreaction mix- Reaction of C1 0 with CH CH (CCl solution).

ture were removed, placed in stoppered vessels (con- 45 taining airabove the mixture) and allowed to react fur- TABLE ther at varioustemperatures as indicated in Table l. The reactions were conducted underordinary laboratory lightling and no precaustions were taken to ex-(MmarRmio Q]2O;CH3CH2C]= clude actinic light from entering the reactingmixtures. The reaction times in Table l are exclusive of the above No T?Fe B C D 2 hour dlssolution period. The mole percentages of materialswere measured by means of vapor phase chro- 2 22 a 2 ga 8'22 ma ogr phy-p-C-)- 3 1 40 90.66 8.47 0.36 0.52 TABLE I 4 24 40 82.96 14.13 1.451.46

" wherein: Reaction Reaction A t'H,.(H.,('l (mnl'i 1 Time emp. B CliCHfl, (mol'i) No (Hrs. 1C A B C D E c (H tc (mul w l o (101,011.,(1 (m1w) 1 7.0 -78 82.7 0.7 1.37 0.11

.40 3 30.0 25 36.4 .20 H04 999 l.4l EXAMPLE 4 wherein.

4 Reaction of Cl O with CH CH Cl (CCL, solution).

Using substantially the same procedure as in EXtil'llple 3, ethylchloride was mixed with a stock solution of C1 0 in CCl (1.668 M) toform a reaction mixture wherein the molar ratio of Cl O:CH CH Cl=l0:l.Portions of the reaction mixtue were allowed to react in ampoules filledas per Example 3 at various temperatures in the dark. The results aresummarized in Table 1V.

C1 0 vs. C1 in Chlorination Reaction.

A series of reactions were conducted to compare the selectivity of C1 0and C1 as chlorinating agents. The reactions conditions were: (a) 25C;(b) inert atmosphere (N2); (c) reactants in solution with CCL, (or CFCI-CFCI (d) sealed glass ampoules, and (e) molar ratio of chlorinatingagent to substrate=l:l0. Some reactions were conducted in the presenceoflight supplied by a 250 watt General Electric Sun Lamp placed inchesfrom the reaction vessels. Other reactions were conducted in the dark.The reaction mixtures were prepared by mixing together solutions ofsubstrate and chlorinating agent in CCl Each reaction was run tocompletion, i.e., until the chlorinating agent was consumed. Thereaction products were analyzed by v.p.c. and the results summarized inTable V.

The products named under Product Ratio above in Table V were the onlyproducts observed via v.p.c. except for trace amounts of otherunidentified products in the chlorination of ClCI-l CHCl Substantiallythe same results were obtained when the Cl- O/dark experiments wereduplicated except the atmospher was air rather than nitrogen.

EXAMPLE 6 Reaction of C1 0 with CH CHCl (CCl solution).

To compare the effect of dehydrating agents upon the reaction rate,solutions of C1 0 and CH CHCl in CCl were prepared such that the ratioof Cl O:Ch CHCl was 1:2. Both reaction mixtures were degassed and sealedin glass ampoules, as described in Example 3. In one ampoule, a slightexcess of an anhydrous Na SO was included as a dehydrating agent. Thereaction mixtures were then allowed to warm to 25C and maintained atthat temperature until the half-life of the reaction was determined,i.e., the time period over which the initial concentration of C1 0 wasdecreased by 50 percent. The results are summarized in Table VI.

Initial concentration in CCL.

We claim:

1. A process for making l,l,l-trichloroethane comprising reacting bycontacting in liquid phase (a) C1 0 with (b) chloroethane,1,1-dichloroethane or a mixture thereof; said process being conductedneat or in an inert solvent selected from the group consisting of liquidperhalogenated hydrocarbons and 1.1.1- trichloroethane at a reactiontemperature of from about 20 to about C under substantially anhydrousconditions in the substantial absence of actinic light.

2. The process defined by claim 1 wherein said reaction temperature isfrom about 0 to about 50C.

3. The process defined by claim 2 wherein said reaction temperature isfrom about 10 to about 40C.

4. The process defined by claim 1 wherein the process is conducted inthe absence of actinic light.

5. The process defined by claim 1 wherein the molar ratio of (a) to (b)is from 1:20 to 20:1.

6. The process defined by claim 5 wherein (a) is present in at least astoichiometric amount.

7. The process defined by claim 1 wherein (a) is present in essentiallya stoichiometric amount.

8. The process defined by claim 1 wherein said solvent is1,1,l-trichloroethane.

9. The process defined by claim 8 wherein said reaction temperature isfrom about 10 to about 40C and wherein (a) is present in at least astoichiometric amount.

UNITED STATES PATENT AND TRADER/LARK OFFICE CERTH IQATE 0E5 UlBEEQEZiQNPATETT'NO. 3,872, 176 DATED March 18, 1975 :N'VENTORiS) Gerald L.Kochanny, Jr. and Thomas A. Chamberlin H IS that effbi appear; me 2b:Viijfififid gt/3:33 and that 33;:5 Paiani are hereby corrected as shownbeiow:

Column 1, .line 53: "Tanner er al." should be -Tanner et al.-.

Column 1, line 54: "l, l, l-trichloropropanes should be --l, l,l-trichloropropane.

Column 1, line 58: "chlorethane" should be chloroethane-.

Column 2, line 65: "producution should be -production-.

Column 3, line 7: "the" should be that-.

Column 3, line 49: "lightling and no precaustions" should be --lightingand no precautions--.

Column 3, Table .1, under Column B: "099.96" should be -9.96--; "8.40"should be -28.40-; and "1.20" should be -4l.20--.

Column 4, line 66: "(CCL 4 solution)" should be -(CCl solution) Column5, line 3: "mixtue" should be -mixture--.

Column 5, Table IV: "Rxn." over column 1, should be moved to the top ofthe column 3 heading Rxn. Temp. (C)-.

Column 5, Table IV: "C" should be moved so it is centered over the lastcolumn.

Column 5, line 26: "reactions" should be reaction-.

Column 5, line 57: "atmospher" should be -atmosphere--.

Signed and Scaled this twenty-third D 3y 0f September 1975 [SEAL] A liesI:

RUTH C. MASON C. MARSHALL DANN 4 713 117 ('mnmiuimu'r n] IUICIIIA andTrudumurks UNITED STATES PATENT AND TRADER/LARK OFFICE CERTH IQATE 0E5UlBEEQEZiQN PATETT'NO. 3,872, 176 DATED March 18, 1975 :N'VENTORiS)Gerald L. Kochanny, Jr. and Thomas A. Chamberlin H IS that effbi appear;me 2b: Viijfififid gt/3:33 and that 33;:5 Paiani are hereby corrected asshown beiow:

Column 1, .line 53: "Tanner er al." should be -Tanner et al.-.

Column 1, line 54: "l, l, l-trichloropropanes should be --l, l,l-trichloropropane.

Column 1, line 58: "chlorethane" should be chloroethane-.

Column 2, line 65: "producution should be -production-.

Column 3, line 7: "the" should be that-.

Column 3, line 49: "lightling and no precaustions" should be --lightingand no precautions--.

Column 3, Table .1, under Column B: "099.96" should be -9.96--; "8.40"should be -28.40-; and "1.20" should be -4l.20--.

Column 4, line 66: "(CCL 4 solution)" should be -(CCl solution) Column5, line 3: "mixtue" should be -mixture--.

Column 5, Table IV: "Rxn." over column 1, should be moved to the top ofthe column 3 heading Rxn. Temp. (C)-.

Column 5, Table IV: "C" should be moved so it is centered over the lastcolumn.

Column 5, line 26: "reactions" should be reaction-.

Column 5, line 57: "atmospher" should be -atmosphere--.

Signed and Scaled this twenty-third D 3y 0f September 1975 [SEAL] A liesI:

RUTH C. MASON C. MARSHALL DANN 4 713 117 ('mnmiuimu'r n] IUICIIIA andTrudumurks UNITED STATES PATENT AND TRADEMARK OFFICE CERTEFICATE 0i?URREITEQN PATEKT'NO. 3,872, 176

DATED March 18, 1975 un-moms) Gerald L. Kochanny, Jr. and Thomas A.Chamberlin Column l, .line 53: "Tanner er al." should be --Tanner etal.-.

Column 1, line 54: "l, l, l-triohloropropanes" should be-l,l,l-trichloropropane.

Column 1, line 58: "chlorethane" should be chloroethane.

Column 2, line 65: "producution" should be production--.

Column 3, line 7: "the should be ---that.

Column 3, line 49: "lightling and no precaustions should be -lightingand no precautions.

Column 3, Table .1, under Column B: "099.96" should be --9.96-; "8.40"should be --28.40-; and "1.20" should be --4l.20-.

Column 4, line 66: "(CCL solution)" should be --(CCl solutiOn),--.

Column 5, line 3: "mixtue" should be -mixture-.

Column 5, Table IV: "Rxn." over column 1, should be moved to the top ofthe column 3 heading --R xn. Temp. C)--.

Column 5, Table IV: "C" should be moved so it is centered over the lastcolumn.

Column 5, line 26: "reactions" should be reaction-.

Column 5, line 57: "atmospher" should be -atmosphere--.

Signgtd and Sealed this twenty-third Day of September 1975 [SEAL]ANE'SI.

RUTH C. MASON C. MARSHALL DANN Alloying ()j'fiver ('ummisxlmlvrnj'lulcnls and Trademarks

1. A PROCESS FOR MAKING 1,1,1-TRICHLOROETHANE COMPRISING REACTING BYCONTACTING IN LIQUID PHASE (A) CL2O WITH (B) CHLOROETHANE,1,1-DICHLOROETHANE OR A MIXTURE THEREOF, SAID PROCESS BEING CONDUCEDNEAT OR IN AN INERT SOLVENT SELECTED FROM THE GROUP CONSISTING OF LIQUIDPERHALOGENATED HYDROCARBONS AND 1,1,1-TRICHLOROETHANE AT A REACTIONTEMPERATURE OF FROM ABOUT -20* TO ABOUT 80*C UNDER SUBSTANTIALLYANHYDROUS CONDITIONS IN THE SUBSTITIAL ABSENCE OF ACTINIC LIGHT.
 2. Theprocess defined by claim 1 wherein said reaction temperature is fromabout 0* to about 50*C.
 3. The process defined by claim 2 wherein saidreaction temperature is from about 10* to about 40*C.
 4. The processdefined by claim 1 wherein the process is conducted in the absence ofactinic light.
 5. The process defined by claim 1 wherein the molar ratioof (a) to (b) is from 1:20 to 20:1.
 6. The process defined by claim 5wherein (a) is present in at least a stoichiometric amount.
 7. Theprocess defined by claim 1 wherein (a) is present in essentially astoichiometric amount.
 8. The process defined by claim 1 wherein saidsolvent is 1,1,1-trichloroethane.
 9. The process defined by claim 8wherein said reaction temperature is from about 10* to about 40*C andwherein (a) is present in at least a stoichiometric amount.